Measurement of Prostate-Specific Antigen and Prostatic Acid ...

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(11 pa- tients), the concentrations of both markers had decreased by five days. Concentrations of prostate-specific antigen but not of prostatic acid phosphatase.
CLIN. CHEM. 37/6, 859-863

(1991)

Measurement of Prostate-Specific Antigen and Prostatic Acid Phosphatase Concentrations in Serum before and 1 -42 Days after Transurethral Resection Prostate and Orchidectomy Alun

Stephen

Price,โ€™

Preoperative

E. A. Attwood,2

intra-individual

variation

John

B. F. Grant,2

for determinations

of prostate-specific antigen and prostatic acid phosphatase concentrations, 15-30% in 92 patients with benign prostatic hyperplasia, limits the diagnostic usefulness of both tumor markers. In benign prostatic hyperplasia (214 patients), concentrations of these tumor markers increased in the initial postoperative period. Prostatic acid phosphatase concentration then decreased by the third postoperative day. Prostate-specific antigen concentration remained above normal in the first postoperative week but had decreased by 42 days. In prostatic carcinoma (46 patients), the concentrations of these tumor markers did not increase postoperatively. During the first week, the concentrations of prostatic acid phosphatase began to fall, but prostate-specific antigen showed a decrease only at 42 days. After orchidectomy (11 patients), the concentrations of both markers had decreased by five days. Concentrations of prostate-specific antigen but not of prostatic acid phosphatase were significantly increased

in patients

with

metastases

at 42 days

post-

operatively. When the concentration of tumor marker did decrease, the magnitude of change was greater for prostatic acid phosphatase than for prostate-specific antigen. These changes were accentuated after an orchidectomy.

AdditIonal

Keyphrases:

benign

prostatic

hyperplasia

tumor

markers

Prostate-specific antigen (PSA), a glycoprotein beto the serine protease group (1-3), is produced only in the prostatic ductal epithelium (4)3 The physiological role of PSA is liquification of seminal fluid (3). Serum PSA concentrations measured before prostateclonging

tomy are increased both in patients with prostatic carcinoma and in those with benign hyperplasia (5-7). Prostatic acid phosphatase (PAP; EC 3.1.3.2) is essential for maintaining normal spermatid metabolism. Both proteins are in current use as tumor markers for prostatic carcinoma. Results of previous studies of PSA concentration in patients with this disease suggest that the test may be useful in screening for carcinoma (8), in directing the preoperative diagnosis (9-13), in monitoring the progression of established disease (10, 12, 14-

Departments

General

Hospital,

3Nonstandard

ofโ€™

Clinical

Chemistry and 2Urology, Northern Sheffield, U.K. PSA, prostate-specific antigen; and TURP, transurethral pros-

Herries Road, abbreviations: acid phosphatase;

PAP, prostatic tatectomy. Received November

15, 1990;

accepted

March

28, 1991.

Trevour

A. Gray,โ€™

and

Kenneth

of the

T. H. Moore2

16), and in monitoring the response to therapy (13, 17-22). In transurethral resection of benign prostatic hyperplasia, most of the adenoma is removed, whereas in transurethral resection of prostatic cancer, removal of tissue is limited to that required to relieve obstruction of outflow from the bladder. In our hospital, radical prostatectomy is not performed. Variation in the amount of tissue removed and the loss of hormonal stimulation of the prostate after an orchidectomy complicate the assessment of the perioperative concentrations of PSA and PAP. We undertook a prospective study to establish the pattern of change of PAP and PSA concentrations in serum directly after transurethral prostat.ectomy (TURP) in patients with prostatic carcinoma and benign hyperplasia. Our aim was to document changes in the serum concentrations of these tumor markers, to improve interpretation of follow-up sampling, and to evaluate whether these changes could be used to distinguish between benign and malignant disease. MaterIals

and Methods

All patients who presented to the Urology in a 12-month period and in whom a prosor orchidectomy was planned were included in the study. The patients were divided into three groups: those with benign hyperplasia treated by TURP, those with carcinoma treated by TURP alone, and those with carcinoma treated by orchidectomy (and no TURP). Patients treated by TURP had an obstruction of bladder outflow. Patients having an orchidectomy had clinical symptoms of already diagnosed prostatic carcinoma, established either by needle biopsy or by a TtJRP done at least three months before the orchidectomy. Patients who underwent both TURP and orchidectomy within three months were excluded from the study. Diagnosis of malignancy was made by histological examination of the resected prostatic tissue or, in the case of those patients undergoing an orchidectomy alone, by needle biopsy. The presence of bony metastases was established by isotope bone scan. Sample collection: We collected 10 mL of venous blood from all patients on the day before the operation and one, three, five, and 42 days after the operation. All samples were taken in the morning and before any digital examination of the prostate. A second preoperative sample was obtained from 92 of the patients with benign prostatic hyperplasia. Tumor marker assays: PAP was measured by radioiznmunoassay (Du Pont UK Ltd., Stevenage, Herts., Patients:

Department tatectomy

CLINICAL CHEMISTRY, Vol. 37, No. 6, 1991

859

U.K.). The interassay imprecision (CV) was 9.2%, 5.4%, and 8.3% at concentrations of 3.1, 10.5, and 26.1 gfL, respectively. PSA was measured by an immunoradiometric method (Hybritech, Nottingham, U.K.). The interassay CV was 6.2%, 5.8%, and 5.3% at concentrations of 4.2, 15.5, and 75.5 tg/L, respectively. Pre- and postoperative concentrations of PSA and PAP were compared by using the Mann-Whitney U test.

Table 2. Percentage of Patients Tumor Marker Concentrations

Days after surgery Cutoff

Tumor marker Benign

1 shows the range of concentrations of each marker before surgery. For both proteins, the serum concentration is significantly (P